View Full Version : Battery Drain

10-12-2015, 03:51 AM
I have a brand new Battery. As soon as I start the car, the Battery goes dead. I saw that the Technical Library is showing the Battery should have 1000 min. cold cranking amps, what happens if my 390 has say 750 cold cranking amps? Also, the wiring around the Voltage Regulator is a real mess. I sent off for a poster size color diagram. I also purchased a new Voltage Regulator. The old one's prongs were bent and broke. The part that plugs into the Voltage Regulator does not look like the one they sell at places like Bird Nest or Bob's Bird House. Also, I have oil leaking on my Alternator leads. Could any of these be the cause of my problem? All advice is appreciated.

NightBird (Ken)

10-12-2015, 10:01 AM
At least the battery is in good shape.
If you have an alternator, it could have a shorted diode or SCR. This problem can be violent, sending all your battery power to ground, or an 'open' diode/SCR could simply put out far less charging amps to refill the battery. Either way, most of the auto parts stores will check your alt for free.

Your original voltage regulator was mechanical. Today, the solid state regulators have taken over because they are better. I don't know how all the connections can be bent if you have a 'plug-in' setup.

I need to ask, are you trying to keep your car 'pure stock'? The reason is, all the old alternators and generators have become 'specialty items' because nobody has made them in years. New alternators come with internal voltage regulators that cost ~$10 to replace. A modern alternator produces 100 amps and is much cheaper than trying to duplicate a 30 amp setup from 1966. Bone yards crush the new ones, daily.

So you have options. 1987-93 Thunderbirds used an alternator that looks just like yours except it has an internal regulator and it outputs 75 amps. Go to rockauto.com and use the 5% discount they offer. You will find everything you need including voltage regulators, alternators and plugs.

Oil will not harm your wiring. - Dave

10-12-2015, 02:42 PM
Dave, Thanks for the response. My Thunderbird is a 1965 Convertible with a 390 engine. The Voltage Regulator that I removed was a NAPA brand. One of the prongs (might be incorrect term) is bent, and one is chipped. I would like to keep my car stock as far as cosmetic's go, but when it comes to mechanical and electrical no. Now, I will need to remove the Alternator to have it tested. If, I have to buy a new one, are you saying a new one will have a Voltage Regulator in it? What happens to the old wiring to the old Voltage Regulator?

NightBird Ken

10-13-2015, 06:43 AM
...1987-93 Thunderbirds used an alternator that looks just like yours except it has an internal regulator and it outputs 75 amps...IF you buy this alternator it already has an internal regulator. Just be sure the mounting fits. You can compare them at NAPA.

All those old wires are gone with the above alt. It simply has two plugs (both available at NAPA). One wire goes to your battery +, and the other wire goes to your key to sense the key is on. That wire is already on your old regulator.